50 TYPES OF BRITISH PLANTS 
over the wilderness of snow. In Switzerland, one may 
note, the chief article of diet is formed by the decaying 
pollen grains which are blown along the snow from the 
great pine forests of the country. 
A microscopic colony of great beauty is the water-net, 
of which the illustration will give a better idea than 
Natural size and top enlarged, 
much verbal description, The cells of the colony “con- 
jugate,” and a new water-net is formed within, escaping 
by rupturing the cell-wall. 
The third class shows a marked development, for 
division of labour has begun. Special cells are set aside 
for reproduction, corresponding to the flowers in higher — 
plants, and of these cells there are now two kinds, which 
